Revenues - Disaggregation of Revenue (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 5,151	$ 3,997	$ 10,016	$ 7,734
Americas
Disaggregation of Revenue [Line Items]
Total revenues	3,596	2,816	6,966	5,433
Europe
Disaggregation of Revenue [Line Items]
Total revenues	1,070	786	2,104	1,541
Asia Pacific
Disaggregation of Revenue [Line Items]
Total revenues	$ 485	$ 395	$ 946	$ 760
Untied States | Geographic Concentration Risk | Revenue
Disaggregation of Revenue [Line Items]
Concentration risk percentage	96.00%	96.00%	96.00%	96.00%
Subscription and support
Disaggregation of Revenue [Line Items]
Total revenues	$ 4,840	$ 3,745	$ 9,415	$ 7,241
Sales Cloud
Disaggregation of Revenue [Line Items]
Total revenues	1,279	1,130	2,524	2,203
Service Cloud
Disaggregation of Revenue [Line Items]
Total revenues	1,303	1,087	2,555	2,107
Salesforce Platform and Other
Disaggregation of Revenue [Line Items]
Total revenues	1,512	912	2,876	1,754
Marketing and Commerce Cloud
Disaggregation of Revenue [Line Items]
Total revenues	$ 746	$ 616	$ 1,460	$ 1,177